Bitcoin's four-year clock.
Every 210,000 blocks — roughly four years — the reward miners earn per block is cut in half. It's the event that paces Bitcoin's supply and, historically, its cycles.
Block rewards halve again in…
The halving happens on a block, not a clock — the date and timer are estimates based on ~10-minute blocks and 84,972 blocks remaining.
What actually happens?
Nothing dramatic at the moment itself — one block is mined, and from the next block on, miners receive half as much new BTC. The effect is slow and structural: the flow of new supply hitting the market halves overnight, and keeps halving every cycle until the last coin is mined around 2140. With demand unchanged, less new supply has historically preceded the cycle's expansion phase — though that's a pattern from only a few cycles, not a guarantee.
Every halving so far
| Date (UTC) | Block | Reward | New BTC / day |
|---|---|---|---|
| Nov 28, 2012 | 210,000 | 50 → 25 BTC | 3,600 |
| Jul 9, 2016 | 420,000 | 25 → 12.5 BTC | 1,800 |
| May 11, 2020 | 630,000 | 12.5 → 6.25 BTC | 900 |
| Apr 20, 2024 | 840,000 | 6.25 → 3.125 BTC | 450 |
| ~2028 next | 1,050,000 | 3.125 → 1.5625 BTC | 225 |
Dates are UTC — the calendar date containing each halving block. Block 840,000 was mined at 00:09:27 UTC on 20 April 2024.